breadth first traversal

Author: Shagunaawasthi

BFS.cpp

@@ -0,0 +1,87 @@
+
+
+#include<iostream>
+#include <list>
+
+using namespace std;
+
+
+class Graph
+{
+    int V;
+
+
+    list<int> *adj;
+public:
+    Graph(int V);
+
+
+    void addEdge(int v, int w);
+
+
+    void BFS(int s);
+};
+
+Graph::Graph(int V)
+{
+    this->V = V;
+    adj = new list<int>[V];
+}
+
+void Graph::addEdge(int v, int w)
+{
+    adj[v].push_back(w);
+}
+
+void Graph::BFS(int s)
+{
+
+    bool *visited = new bool[V];
+    for(int i = 0; i < V; i++)
+        visited[i] = false;
+
+    list<int> queue;
+
+    visited[s] = true;
+    queue.push_back(s);
+
+
+    list<int>::iterator i;
+
+    while(!queue.empty())
+    {
+
+        s = queue.front();
+        cout << s << " ";
+        queue.pop_front();
+
+
+        for (i = adj[s].begin(); i != adj[s].end(); ++i)
+        {
+            if (!visited[*i])
+            {
+                visited[*i] = true;
+                queue.push_back(*i);
+            }
+        }
+    }
+}
+
+// Driver program to test methods of graph class
+int main()
+{
+
+    Graph g(4);
+    g.addEdge(0, 1);
+    g.addEdge(0, 2);
+    g.addEdge(1, 2);
+    g.addEdge(2, 0);
+    g.addEdge(2, 3);
+    g.addEdge(3, 3);
+
+    cout << " Breadth First Traversal "
+         << "(starting from vertex 0) \n";
+    g.BFS(0);
+
+    return 0;
+}